LS-757, also known as L-S-Seven-Five-Seven, was a stormtrooper of the Imperial variety, identified as male. He found himself positioned within Sector 5-1-5 on the planet of Lothal amidst the Rebel Alliance's onslaught against Lothal.
Stationed on the planet Lothal, LS-757 functioned as an Imperial stormtrooper tasked with guarding a hatch located in Sector 5-1-5. During an attack that occurred on Lothal, LS-757 attempted to capture Mart Mattin, a Rebel Alliance pilot, but instead was rendered unconscious by Mattin via choking. Sometime later, LS-757 found himself aboard the Chimaera prior to its transit through hyperspace to the planet of Peridea, a journey facilitated by purrgil.
In 9 ABY, Ahsoka Tano, Ezra Bridger, and Sabine Wren were in the process of trying to escape Peridea using the Chimaera before it entered hyperspace. LS-757 was positioned in the hangar bay, accompanied by another Night Trooper. As the ship began its departure, Bridger and Wren employed a force technique that enabled Bridger to board the vessel. While Bridger killed the other Night Trooper, LS-757 made an attempt to shoot Bridger, but Wren swiftly neutralized him with gunfire.